Researchers at Harvard School of Public Health (HSPH) and Brigham and Women’s Hospital (BWH) in Boston have published a new meta-analysis in the September 21, 2011 issue of the Journal of the American Medical Association that links depression to stroke risk. The researchers surveyed the medical literature for all studies involving depression as a risk factor for stroke. They found that depression increased the risk of stroke by 45% and elevated the risk of dying from a stroke by 55%, compared with individuals who were not depressed. They also found that studies that measured depression by clinical diagnosis showed a much stronger association with stroke, compared with studies that measured depression by self-reported symptom scales.

While depression has been linked to heart disease, cancer, and type 2 diabetes, findings on a possible link to stroke have been inconsistent.

In the current study, “Depression and Risk of Stroke Morbidity and Mortality: A Meta-analysis and Systematic Review,” lead researcher An Pan, research fellow in HSPH’s Department of Nutrition, and colleagues found 28 prospective cohort studies involving more than 317,000 participants followed up for stroke incidence for 2 to 29 years. The investigators found depression contributed to the risk of stroke and dying from stroke nearly as often as known risk factors such as smoking and obesity.